Solenoids are used for a pressing operation of various devices such as a control valve. The solenoid includes a coil wound around a bobbin, a yoke, and a plunger in order from the outer side toward an inner circumferential side of a cylindrical case section. Magnetic attraction force is generated between the coil and the yoke by supplying electricity to the coil. The columnar plunger including an output shaft at the central portion is slidably moved along an axial direction of the yoke by being affected by the magnetic attraction force (refer to US2011/0210277A (Reference 1)).
In the solenoid in Reference 1, the yoke includes a tubular portion on an outer circumferential side of the plunger, a top plate portion formed on a tip end of the tubular portion in a radial direction, and a guide portion that is formed to extend from the top plate portion toward an outer circumferential side of the output shaft. The guide portion guides the movement of the plunger, and the sliding movement can be performed until a convex portion formed on an outer circumference of the output shaft comes into contact with an end of the guide portion. As described above, the solenoid in Reference 1 has a structure in which the output shaft of the plunger is guided by the yoke so as to move the plunger.
In the solenoid in Reference 1, since the yoke has the tubular portion, the top plate portion, and the guide portion, the structure becomes complex, and thus the processing becomes complex. In addition, the guide portion of the yoke guides the movement of the plunger, and regulates the movement of the plunger by coming into contact with an end face of the plunger. Since the guide portion does not contribute to generation of the magnetic attraction force, it is not reasonable that the guide portion is integrally formed with the tubular portion of the yoke via the top plate portion.